• 월간산업보건
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• s.263
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• pp.47-52
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• 2010

• 월간산업보건
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• s.369
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• pp.38-49
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• 2019

• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.212-219
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• 2003

In construction project planning and control, a cost model performs a critical role such as cost determination on a contract stage and cost tracing. The model can maximize owner's profit and value within the project budget and optimize cost management works on overall construction implementation stages. A BoQ(Bill of Quantities) generally adopted in a unit price contract has been applied as an important tool for cost control and forecast. However a previous cost model based on the BoQ has shown limitations in that it requires too detailed information and heavy manpower on cost management and difficulty in keeping relationship with construction planning, scheduling and progress management. The each cost items and unit prices which constitute of construction works are individually very important management factors but the relative weight for each items and prices have a difference on the contents and conditions of each conditions of each construction works. In consideration of this structural mechanism of cost determination, this research is aimed at examining the critical factors affecting the construction cost determination and propose and verify a new cost forecasting model which is more simple and efficient and also keeps the accuracy of cost management.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.83-92
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• 2009

Complicated business logic makes program complexity more complicated. It's inevitable that the program must undergo reengineering processes all the way of in its lifetime. Hot spot analysis that has diverse purposes is getting an important question more and more. As a rule, reengineering process is done by UML model-based approach to analyze the legacy system. The smallest fragment of targets to be analysed is unit, that is function or class. Today's software development is to deal with huge change of software product and huge class including heavy quantity of LOC(Lines Of Code). However, analysis of unit is not precise approach process for reliable reengineering consequence. In this paper, we propose very precise hot spot analysis approach using Aspect-Oriented Programming languages, such as AspectJ. Typically the consistency between UML and source is needed code to redefine the modified library or framework boundaries. But reengineering approach using AOP doesn't need to analyze UML and source code. This approach makes dynamic event log data that contains detailed program interaction information. This dynamic event log data makes it possible to analyze hot spot.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.451-457
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• 2009

This study was conducted to evaluate the felling productivity by chain saw in thinning operation of Korean pine (Pinus koraiensis) stands. Time study data were collected from 4 thinning site in Korean pine stands. This study derived a regression model to estimate the average felling cycle time for evaluating the productivity in felling, which was used to analyze the felling productivity by thinning period. In the study sites, the average felling cycle time per a tree was 463 sec/cycle and the productivity was $2.26m^3/hr$. Thinning period in Korean pine is divided into three groups by producing purposes; small-diameter log, medium-diameter log, and large-diameter log. And analyzed working time and productivity from thinning period fixed by producing purposes. For the small-diameter log producing purpose estimated to be thinning period operated once when the mean DBH was 16 cm and its productivity was $8.94m^3/man{\cdot}day$. For the medium-diameter and large-diameter log producing purposes, thinning period was twice and three times when the mean DBH of the 1st and 2nd thinning period was 16 cm and 21 cm, and its productivity was $9.06m^3/man{\cdot}day$ and $10.86m^3/man{\cdot}day$. The 30 cm in DBH and $15.12m^3/man{\cdot}day$ in productivity was operated 3rd thinning for the large-diameter log producing purposes.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1502-1510
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• 1999

In adaptive job allocation method for multiprocessor systems a job is folded, or split in two halves, to fit for an available subcube in order to reduce the waiting time of jobs. In this method, however, since a job is folded whenever a subcube with the proper size is not found, the prolonged execution time caused by job split may override the savings in waiting time, in which case the total adaptive jobs may be increased. In this paper, an improved adaptive job allocation algorithm, called Estimate-fold allocation, Is presented and evaluated. The proposed algorithm estimates the costs and takes the better of two alternatives ; folding right away and waiting until a bigger subcube becomes available. The average total job execution cost of our algorithm is calculated and compared to those of the conventional adaptive, buddy, and gray-code algorithms through simulations. The results shows that our proposed algorithm performs better than others.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.137-145
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• 2006

Calculating non-working days is very important element for the accurate estimation of construction time. And non-working days are largely affected by weather factors such as rainfall, wind velocity, snowfall and temperature. In the case of concrete works, there are lots of referable information for the calculation of non-working days due to the weather factors. However, for the structural steel works, there are very limited information only. Through literature survey and interviews with a few engineers, this paper established the weather factors that affect steel structural works and the impact of those factors. Based on the factors and the expected impact of the factors together with the weather data during the last 15 years in Seoul region gathered from Korea Meteorological Administration, this paper suggests the monthly non-working day of structural steel work due to weather factors. This information can be used for the early estimation of construction time.

• Transactions of Materials Processing
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• v.1 no.2
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• pp.32-39
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• 1992

대형 강괴의 자유단조 공정 중에서 코깅(cogging)작업은 강괴 단조의 초기에 단면을 줄이면서 길이 방향으로 늘리는 작업이다. 코깅 작업의 역활은 주조시 발생하는 강괴 내부의 기공을 압착시켜 제거하며 주조 조직을 파괴하여 물성치를 균질화하고 향상시키는 것이다. 그러나 대형강괴의 작업에는 제약조건이 많이 있고 작업공정에서 공정변수도 여러가지 이다. 따라서 본 논문에서는 변형해석과 온도해석을 할 수 있는 3차원 열-점소성 유한요소해석 프로그램을 개발하고, 코깅공정에서 다이의 형상과 다이폭, 다이 겹침과 엇갈리기, 강괴의 온도 구배, 압하 깊이와 패스 설계등의 여러 공정 변수의 영향을 해석하여, 단조 효과를 최대화하는 최적의 단조 공정을 예측하여 공정개선에 적용하는 것이 목적이다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.15-16
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• 2015

해저파이프라인 및 해저케이블 설치해역이 대수심으로 이동함에 따라 육지와는 다른 열악한 시공 환경에 놓이게 된다. 이때 파이프라인 및 케이블이 매설되는 해저지반 상태와 작업이 이루어지는 해역의 해상조건 등은 작업효율에 영향을 미치기 때문에 효율적인 시공이 필요하다. 본 논문은 구조물 매설에 앞서 해저지반 굴삭 작업을 수행하기 위해 ROV 트렌쳐의 하단에 장착되는 워터젯 굴삭기의 작업효율 및 시공성능 추정에 관한 연구이다. 먼저 전산유체해석을 통해 워터젯 굴삭기의 굴삭효율을 극대화할 수 있는 노즐 수량을 정하였고, 모형실험을 수행하여 굴삭기의 시공성능을 예측할 수 있는 최대 굴삭심도 및 최대 굴삭속도를 파악하였다. 이를 바탕으로 실제 운용중인 워터젯 굴삭장비들과 시공성능을 비교 분석하였다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.101-102
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• 2023

건설 현장에서 발생하는 사고가 전체 산업재해의 약 20~30%로 높은 비율을 보이고 있기 때문에, 위험성평가를 통해 위험을 감지하고 대책을 수립하는 것이 중요하다. 이 연구의 목적은 현장의 모든 관리자 및 근로자들이 참여하고 정보를 공유함으로써 근로자들의 안전한 작업환경을 조성하고, 건설현장 근로자의 안전의식과 안전문화를 형성하여 안전사고를 미연에 예방하기 위한 위험성평가 프레임워크 개발에 있다. 이를 통해 종합적인 안전관리를 실현하고, 안전한 작업환경을 조성하며, 근로자의 안전의식을 높이고 안전문화를 정착시키는 것이 주요 목적이다. 본 연구에서는 디지털 플랫폼을 활용하여 건설현장에 적합한 위험성평가 프레임워크를 개발하고자 한다. 이 프레임워크를 통해 안전한 작업환경을 조성하고, 건설현장 근로자의 안전의식과 안전문화를 형성하여 안전사고를 미연에 예방할 수 있다. 이러한 연구결과는 안전한 작업환경 조성과 안전사고 미연에 예방하는데 중요한 역할을 할 것으로 예측가능하다.